Z|[\+-]\d{2}.\d{2})'; /** * @param integer|null $timestamp unix timestamp * @return \DateTime|null */ public static function timestampToDateTime($timestamp) { if($timestamp === null) { return null; } elseif(is_int($timestamp)) { $dt = new \DateTime(); $dt->setTimestamp($timestamp); return $dt; } else { throw new \InvalidArgumentException('expected integer or null'); } } /** * @param string|null $text * @return \DatePeriod|null */ public static function parse($text) { if($text === null) { return null; } else { if(preg_match( '/^(?P\d{4})-(?P\d{2})-(?P\d{2})' .'([ T](?P\d{2}):(?P\d{2})(:(?P\d{2}))?)?' . '(' . self::_timezone_iso_pattern . ')?$/', $text, $attr )) { $start = new \DateTime($text); if(!empty($attr['s'])) { $interval = new \DateInterval('PT1S'); } elseif(!empty($attr['i'])) { $interval = new \DateInterval('PT1M'); } else { $interval = new \DateInterval('P1D'); } return new \DatePeriod($start, $interval, 0); } elseif(preg_match('/^\d{4}-(?P\d{2})(( (?=-)| ?(?!-))' . self::_timezone_iso_pattern . ')?$/', $text, $attr)) { return new \DatePeriod( new \DateTime($text), new \DateInterval('P1M'), 0 ); } elseif(preg_match('/^(?P\d{4})( ?' . self::_timezone_iso_pattern . ')?$/', $text, $attr)) { return new \DatePeriod( new \DateTime(sprintf( '%s-01-01 %s', $attr['y'], isset($attr['tz']) ? $attr['tz'] : '' )), new \DateInterval('P1Y'), 0 ); } else { throw new \InvalidArgumentException( sprintf("could not parse string '%s'", $text) ); } } } /** * @param string|null $text * @return \DateTime|null */ public static function parseGetStart($text) { $period = self::parse($text); if($period) { return $period->start; } else { return null; } } public static function deinvertInterval(\DateInterval $source = null) { // \DateInterval does not implement clone. // @see https://bugs.php.net/bug.php?id=50559 $result = unserialize(serialize($source)); if($result->invert) { $result->y *= -1; $result->m *= -1; $result->d *= -1; $result->h *= -1; $result->i *= -1; $result->s *= -1; $result->invert = 0; } return $result; } /** * @param \DateInterval|null $i * @return string|null */ public static function intervalToIso(\DateInterval $i = null) { if(is_null($i)) { return null; } elseif(sizeof(get_object_vars($i)) == 0) { throw new \InvalidArgumentException( sprintf("given interval is invalid\n%s", print_r($i, true)) ); } else { $i = self::deinvertInterval($i); if($i->y < 0 || $i->m < 0 || $i->d < 0 || $i->h < 0 || $i->i < 0 || $i->s < 0) { throw new \Exception('negative intervals are not supported'); } else { return $i->format('P%yY%mM%dDT%hH%iM%sS'); } } } /** * @param \DatePeriod|null $p * @return string|null */ public static function periodToIso(\DatePeriod $p = null) { if(is_null($p)) { return null; } else { // Cave: // (new \DatePeriod( // new \DateTime('2016-08-05T14:50:14Z'), // new \DateInterval('P1D'), // -1 // )->recurrences == 1 if($p->recurrences <= 0) { throw new \Exception( 'conversion of periods with number of occurances' . ' being negative is not supported' ); } $repetitions = -1; foreach($p as $dt) { $repetitions++; // printf("%d. %s\n", $repetitions, $dt->format(\DateTime::ATOM)); } // \DatePeriod::getStartDate() is available from php 5.6.5. $start_iso = $p->start->format(\DateTime::ATOM); // \DatePeriod::getDateInterval() is available from php 5.6.5. // \DatePeriod::$interval returned an invalid \DatePeriod instance // in php 7.0.8 $interval_iso = self::intervalToIso(get_object_vars($p)['interval']); switch($repetitions) { case -1: // no valid date within period // e.g. new \DatePeriod( // new \DateTime('2016-08-05T14:50:14+08:00'), // new \DateInterval('PT1S'), // new \DateTime('2016-08-05T14:50:14+08:00') // ) throw new \InvalidArgumentException( 'given period does not contain any valid date' ); case 0: return sprintf('%s/%s', $start_iso, $interval_iso); default: return sprintf('R%d/%s/%s', $repetitions, $start_iso, $interval_iso); } } } }